CROSS-REFERENCE TO RELATED APPLICATION
[0001] This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent
Application No.
2014-161004 filed in Japan on August 7, 2014, the entire contents of which are hereby incorporated
by reference.
TECHNICAL FIELD
[0002] This invention relates to a fluorochemical surface treating agent, more particularly
to a fluorochemical surface treating agent comprising a hydrolyzable group-containing
silane modified with a fluorooxyalkylene-containing polymer and/or a partial hydrolytic
condensate thereof, capable of forming a coating having water/oil repellency and mar
resistance, especially chemical resistance, and an article treated therewith.
BACKGROUND ART
[0003] For better appearance and visibility, there is recently an increasing need for the
technology for tailoring the surface of optical articles to be fingerprint proof or
easy in stain removal. In particular, since eyeglass lenses, wearable terminals, and
touch panel displays are readily fouled with stains like sebum, it is desired to form
a water/oil repellent layer on their surface. In the state-of-the-art, there are available
surface treating agents having antifouling, stain wipe-off, abrasion resistance and
mar resistance. However, they are insufficient in chemical resistance, leaving the
problem that their performance is degraded with fingerprints and detergents with the
lapse of time.
[0004] Generally, fluorooxyalkylene-containing compounds exhibit, by virtue of their extremely
low surface free energy, water/oil repellency, chemical resistance, lubricity, parting,
antifouling and other properties. Taking advantage of these properties, they find
use in a variety of industrial fields as water/oil repellent antifouling agents for
paper and textiles, lubricants for magnetic recording media, oil-repellent agents
for precision instruments, parting agents, cosmetic ingredients, protective films
and the like. Inversely, the same properties indicate non-tackiness or non-adhesion
to other substrates. Even if they can be coated to the substrate surface, it is difficult
for the coating to tightly adhere thereto.
[0005] On the other hand, silane coupling agents are well known for their ability to bond
surfaces of glass or fabric substrates to organic compounds. They are widely used
as surface coating agents for numerous substrates. The silane coupling agent contains
an organic functional group and a reactive silyl group (typically hydrolyzable silyl)
in the molecule. In the presence of airborne moisture or the like, the hydrolyzable
silyl groups undergo self-condensation reaction to form a coating. As the hydrolyzable
silyl groups form chemical and physical bonds with the surface of glass or fabric,
the coating becomes a tough coating having durability.
[0006] Patent Document 1 discloses a fluorooxyalkylene group-containing silane represented
by the following formula.
Herein Rf is a divalent linear perfluorooxyalkylene group, R is C
1-C
4 alkyl or phenyl, X is a hydrolyzable group, n is an integer of 0 to 2, m is an integer
of 1 to 5, and a is 2 or 3. When treated with this fluorooxyalkylene-containing silane,
glass and antireflective film are improved in stain wipe-off. However, since both
terminal groups are bonded to the substrate, surface lubricity is insufficient, and
the coating is less satisfactory in sliding and mar resistance.
Citation List
DISCLOSURE OF INVENTION
[0008] In Patent Document 2, the inventors proposed a fluorooxyalkylene-containing silane
of the formula shown below. When glass is treated with the fluorooxyalkylene-containing
silane, improvements in lubricity and mar resistance are available. However, this
still fails to meet the requirements of mar resistance and chemical resistance which
become severer in these days.
Herein Rf is -(CF
2)
d-(OC
2F
4).(OCF
2)
f-O(CF
2)
d-, A is a monovalent fluorinated group terminated with a -CF
3 group, Q is a divalent organic group, Z is a di- to octa-valent organopolysiloxane
residue having a siloxane bond, R is C
1-C
4 alkyl or phenyl, X is a hydrolyzable group, a is 2 or 3, b is an integer of 1 to
6, c is an integer of 1 to 5, α is 0 or 1, d is independently an integer of 0 to 5,
e is an integer of 0 to 80, f is an integer of 0 to 80, the sum e+f is an integer
of 5 to 100, and the repeating units may be randomly arranged.
[0009] Also the inventors proposed a polymer composition in Patent Document 2 and a fluorooxyalkylene-containing
silane of the formula shown below in Patent Document 3, both forming a chemical resistance
film. They are still insufficient to meet both mar resistance and chemical resistance
because the requirement of mar resistance becomes outstandingly severer in these days.
Herein Rf is a divalent perfluorooxyalkylene-containing group, X is -(CH
2)
nSiX' or hydrogen, one or less of X is hydrogen, n is an integer of 2 to 10, and X'
is a hydrolyzable group.
[0010] While touch panel displays and wearable terminals are generally surface coated with
water/oil repellent layers, it is desirable from the aspects of scratch resistance
and fingerprint wipe-out that the water/oil repellent layers have a low coefficient
of dynamic friction. In this regard, it is desired to develop a water/oil repellent
layer having improved mar resistance and a low coefficient of dynamic friction. Since
these terminals are intended for outdoor use as well, the layer is also required to
be resistant to salt water, acid and alkali.
[0011] An object of the invention is to provide a fluorochemical surface treating agent
comprising a hydrolyzable group-containing silane modified with a fluorooxyalkylene-containing
polymer and/or a partial hydrolytic condensate thereof, capable of forming a water/oil
repellent layer having significantly improved mar resistance as well as chemical resistance,
and an article treated therewith.
[0012] The inventors have found that when forming a film, a polymer based on a fluorooxyalkylene
structure backbone and having a hydrolyzable group at one end of its molecular chain
imparts better mar resistance to the film than a polymer based on a fluorooxyalkylene
structure backbone and having hydrolyzable groups at both ends of its molecular chain.
It has been found that a fluorochemical surface treating agent comprising a polymer
based on a fluorooxyalkylene structure backbone, having a siloxane bond-free linking
group, and having a plurality of hydrolyzable groups forms a water/oil repellent layer
having improved mar resistance and chemical resistance.
[0013] In one aspect, the invention provides a fluorochemical surface treating agent comprising
(A) a hydrolyzable group-containing silane modified with a fluorooxyalkylene-containing
polymer, represented by the average compositional formula (1) and/or a partial hydrolytic
condensate thereof.
Herein A is a monovalent fluorinated group terminated With -CF
3; Rf is -(CF
2)
d-(OCF
2)
p(OCF
2CF
2)
q(OCF
2CF
2CF
2)
r-(OCF
2CF
2CF
2CF
2)
s (OCF (CF
3)CF
2)
t-O(CF
2)
d-, d is independently an integer of 0 to 5, p, q, r, s and t are each independently
an integer of 0 to 200, p+q+r+s+t is 10 to 200, units in parentheses may be randomly
arranged; Q is a single bond or a divalent organic group; B is a divalent group: -J
2C-, a divalent group: -L
2Si-, a trivalent group: -JC=, a trivalent group: -LSi=, a tetravalent group: -C≡,
or a tetravalent group: -Si=, wherein J is independently an alkyl group, hydroxyl
group or silyl ether group: K
3SiO-, K is independently hydrogen, alkyl, aryl or alkoxy, L is independently alkyl,
alkoxy or chloro; R is a monovalent organic group; X is a hydrolyzable group, a is
an integer of 1 to 3, b is an integer of 1 to 3, an average of b being 1.5 to 3.0,
c is an integer of 1 to 10.
[0014] The surface treating agent may further comprise (B) a hydrolyzable group-containing
silane modified with a fluorooxyalkylene-containing polymer, represented by the average
compositional formula (2) and/or a partial hydrolytic condensate thereof, wherein
component (B) is present in an amount of 0.1 to 20 mol% based on the total moles of
components (A) and (B),
wherein Rf, Q, B, R, X, a, b, and c are as defined in formula (1).
[0015] The surface treating agent may further comprise (C) a fluorooxyalkylene-containing
polymer having the general formula (3), wherein component (C) is present in an amount
of 0.1 to 40 mol% based on the total moles of components (A), (B) and (C), provided
that component (B) is optional.
D-Rf-D (3)
wherein Rf is as defined in formula (1) and D is independently fluorine, hydrogen,
or a monovalent fluorinated group terminated with -CF
3, -CF
2H or -CFH
2.
[0016] In a preferred embodiment, Q is a single bond or a substituted or unsubstituted,
divalent hydrocarbon group of 2 to 12 carbon atoms which may contain at least one
structure selected from an amide bond, ether bond, ester bond, diorganosilylene group,
and -Si [OH] [(CH
2)
gSi(CH
3)
3]- wherein g is an integer of 2 to 4.
[0017] In a preferred embodiment, X is a hydrolyzable group selected from the group consisting
of C
1-C
10 alkoxy groups, C
2-C
10 alkoxyalkoxy groups, C
1-C
10 acyloxy groups, C
2-C
10 alkenyloxy groups, halogen groups, and silazane groups.
[0018] Typically, the surface treating agent is diluted with a solvent. The solvent is preferably
selected from among methyl perfluorobutyl ether, ethyl perfluorobutyl ether, methoxyperfluoroheptene,
decafluoropentane, pentafluorobutane, and perfluorohexane.
[0019] Also contemplated herein is an article, specifically optical article, which is treated
with the surface treating agent defined above. Typical of the article are glass, chemically
strengthened glass, physically strengthened glass, SiO
2-deposited glass, sapphire glass, SiO
2-deposited sapphire glass, quartz substrate, and metal, which are treated with the
surface treating agent defined above. Most preferred are a touch panel, antireflective
film, wearable terminal, eyeglass lens, and solar cell panel which are treated with
the surface treating agent defined above.
ADVANTAGEOUS EFFECTS OF INVENTION
[0020] A fluorochemical surface treating agent comprising a hydrolyzable group-containing
silane modified with a fluorooxyalkylene-containing polymer and/or a partial hydrolytic
condensate thereof forms a film having improved mar resistance and chemical resistance.
When articles are treated with the surface treating agent, the articles are endowed
with water/oil repellency, fingerprint wipe-out, mar resistance and chemical resistance.
By virtue of mar resistance and chemical resistance, water/oil repellency lasts long.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0021] The notation (Cn-Cm) means a group containing from n to m carbon atoms per group.
Me stands for methyl.
[0022] The invention provides a fluorochemical surface treating agent comprising (A) a hydrolyzable
group-containing silane modified with a fluorooxyalkylene-containing polymer, represented
by the average compositional formula (1), referred to as "single end hydrolyzable
polymer" hereinafter, and/or a partial hydrolytic condensate thereof, and preferably
further comprising (B) a hydrolyzable group-containing silane modified with a fluorooxyalkylene-containing
polymer, represented by the average compositional formula (2), referred to as "dual
end hydrolyzable polymer" hereinafter, and/or a partial hydrolytic condensate thereof,
or (C) a fluorooxyalkylene-containing polymer represented by the general formula (3),
referred to as "nonfunctional polymer" hereinafter.
D-Rf-D (3)
Herein A is a monovalent fluorinated group terminated with -CF
3; Rf is -(CF
2)
d-(OCF
2)
p (OCF
2CF
2)
q (OCF
2CF
2CF
2)
r-(OCF
2CF
2CF
2CF
2)
s(OCF(CF
3)CF
2)
t-O(CF
2)
d-, d is independently an integer of 0 to 5, p, q, r, s and t are each independently
an integer of 0 to 200, p+q+r+s+t is 10 to 200, units in parentheses may be randomly
arranged; Q is a single bond or a divalent organic group; B is a divalent group: -J
2C-, a divalent group: -L
2Si-, a trivalent group: -JC=, a trivalent group: -LSi=, a tetravalent group: -C≡,
or a tetravalent group: -Si=, wherein J is independently an alkyl group, hydroxyl
group or silyl ether group: K
3SiO-, K is independently hydrogen, alkyl, aryl or alkoxy, L is independently alkyl,
alkoxy or chloro; R is a monovalent organic group; X is a hydrolyzable group, a is
an integer of 1 to 3, b is an integer of 1 to 3, an average of b is 1.5 to 3.0, c
is an integer of 1 to 10; D is independently fluorine, hydrogen, or a monovalent fluorinated
group terminated with -CF
3, -CF
2H or -CFH
2.
[0023] In formulae (1) to (3), Rf indicative of the backbone structure of fluorooxyalkylene-containing
polymer is represented by -(CF
2)
d-(OCF
2)
p(OCF
2CF
2)
q(OCF
2CF
2CF
2)
r-(OCF
2CF
2CF
2CF
2)
s(OCF(CF
3)CF
2)
t-O(CF
2)
d-. Herein, d is independently an integer of 0 to 5, preferably 0 to 2, and more preferably
1 or 2; p, q, r, s and t are each independently an integer of 0 to 200, preferably
p is an integer of 10 to 150, q is an integer of 10 to 150, r is an integer of 0 to
20, s is an integer of 0 to 20, t is an integer of 0 to 20, p+q+r+s+t is an integer
of 10 to 200, preferably 20 to 150, and more preferably 30 to 100. Units in parentheses
may be randomly arranged. If one of p, q, r, s and t exceeds 200, the fluorooxyalkylene
group has too high a molecular weight, and the functionality equivalent of hydrolyzable
silyl group is accordingly reduced, resulting in poor adhesion to the substrate and
low reactivity on synthesis. If p+q+r+s+t exceeds the upper limit, chemical resistance
is adversely affected. If p+q+r+s+t is below the lower limit, fingerprint wipe-out
and abrasion resistant properties characteristic of fluorooxyalkylene are not fully
exerted, that is, fingerprint wipe-out and abrasion resistance are adversely affected.
[0024] Illustrative examples of Rf are given below.
-(CF
2)
d'(OCF
2CF
2)
q'O(CF
2)
d'-
-(CF
2)
d'(OCF
2CF
2CF
2)
r'O(CF
2)
d'-
-(CF
2)
d'(OCF
2)
p'(OCF
2CF
2)
q'O(CF
2)
d'-
-(CF
2)
d'(OCF
2)
p'(OCF
2CF
2)
q'(OCF
2CF
2CF
2)
r'O(CF
2)
d'-
-(CF
2)
d'(CF
2)
p'(OCF
2CF
2)
q'(OCF
2CF
2CF
2CF
2)
s'O(CF
2)
d'-
-(CF
2)
d'(OCF
2)
p'(OCF
2CF
2)
q'(OCF
2CF
2CF
2)
r'(OCF
2CF
2CF
2CF
2)
s'O(CF
2)
d'-
Herein d', p' and q' are as defined for d, p and q, respectively, r', s' and t' each
are an integer of at least 1, with their upper limit being the same as r, s and t.
[0025] In formula (1), A is a monovalent fluorinated group terminated with -CF
3, preferably C
1-C
6 perfluoro group, and more preferably -CF
3 or -CF
2CF
3.
[0026] In formulae (1) and (2), Q is a single bond or divalent organic group. The single
bond is a link between Rf group and B group. The divalent organic group is preferably
an optionally substituted, divalent organic group of 2 to 12 carbon atoms, preferably
optionally substituted, divalent hydrocarbon group of 2 to 12 carbon atoms, which
may contain one or more structure selected from an amide bond, ether bond, ester bond,
diorganosilylene group (e.g., dimethylsilylene, diethylsilylene and diphenylsilylene),
and -Si[OH][(CH
2)
gSi(CH
3)
3]- wherein g is an integer of 2 to 4.
[0027] Examples of the optionally substituted, divalent hydrocarbon group of 2 to 12 carbon
atoms include alkylene groups such as ethylene, propylene (trimethylene, methylethylene),
butylene (tetramethylene, methylpropylene), hexamethylene and octamethylene, arylene
groups such as phenylene, and combinations of two or more thereof (e.g., alkylene-arylene),
as well as substituted forms of the foregoing in which some or all hydrogen atoms
are substituted by halogen atoms such as fluorine, chlorine, bromine and iodine. Inter
alia, optionally substituted C
2-C
4 alkyl and phenyl groups are preferred.
[0028] Illustrative examples of Q are given below.
-CH
2O(CH
2)
h-
-CF
2O(CH
2)
h-
Herein h is an integer of 2 to 4.
[0029] In formulae (1) and (2), B is a divalent group: -J
2C-, a divalent group: -L
2Si-, a trivalent group: -JC=, a trivalent group: -LSi=, a tetravalent group: -C≡,
or a tetravalent group: -Si≡. Herein J is independently alkyl, preferably C
1-C
3 alkyl, hydroxyl group or silyl ether group: K
3SiO-; K is independently hydrogen, alkyl, preferably C
1-C
3 alkyl, aryl such as phenyl, or alkoxy, preferably C
1-C
3 alkoxy; and L is independently alkyl, preferably C
1-C
3 alkyl, alkoxy, preferably C
1-C
3 alkoxy or chloro.
[0031] In formulae (1) and (2), X is each independently a hydrolyzable group. Suitable hydrolyzable
groups include C
1-C
10 alkoxy groups such as methoxy, ethoxy, propoxy and butoxy, C
2-C
10 alkoxyalkoxy groups such as methoxymethoxy and methoxyethoxy, C
1-C
10 acyloxy groups such as acetoxy, C
2-C
10 alkenyloxy groups such as isopropenoxy, halogen groups such as chloro, bromo and
iodo, and silazane groups. Inter alia, methoxy, ethoxy, isopropenoxy and chloro are
preferred.
[0032] In formulae (1) and (2), R is a monovalent organic group, preferably a C
1-C
4 alkyl group such as methyl, ethyl, propyl or butyl, or a phenyl group. Most preferred
is methyl.
[0033] The subscript a is an integer of 1 to 3, and preferably 2 or 3 for reactivity and
substrate adhesion. The subscript b is an integer of 1 to 3, an average of b is 1.5
to 3.0, preferably 1.8 to 3.0. If an average of b is less than 1.5, chemical resistance
is adversely affected. If an average of b exceeds 3.0, which means more hydrolyzable
groups, there may arise problems including viscosity buildup, complicated preparation,
low shelf stability, and low water/oil repellency due to a low content of non-fluorinated
group. The subscript c is an integer of 1 to 10, preferably 3 to 8.
[0034] The single end hydrolyzable polymer of formula (1) has 1 to 9, preferably 4 to 9
hydrolyzable groups X. The dual end hydrolyzable polymer of formula (2) has 2 to 18,
preferably 8 to 18 hydrolyzable groups X.
[0035] In formula (3), D is independently fluorine, hydrogen, or a monovalent fluorinated
group terminated with -CF
3, -CF
2H or -CFH
2. Examples of the fluorinated group terminated with -CF
3, -CF
2H or -CFH
2 are given below.
-CF
3
-CF
2CF
3
-CF
2CF
2CF
3
-CF
2H
-CFH
2
[0036] Examples of the single end hydrolyzable polymer of formula (1) wherein linking group
Q is -CH
2-O-C
3H
6-, B is -Si≡, and X is -OCH
3 are shown below. The combination of Q, B and X is not limited thereto, and a series
of single end hydrolyzable polymers are available by merely changing Q, B and X. The
benefits of the invention are obtainable from a surface treating agent comprising
any of such single end hydrolyzable polymers.
The units in parentheses may be randomly arranged.
[0038] The compound of formula (1) may be prepared by any well-known methods. For example,
a single end hydrolyzable polymer of the following formula:
may be prepared by starting with a fluorooxyalkylene-containing polymer modified with
a hydroxyl group at a single end, reacting the polymer with allyl bromide to introduce
an unsaturated bond group at the end, adding chlorosilane, and effecting Grignard
reaction to introduce a plurality of unsaturated bonds. This is followed by adding
chlorosilane to unsaturated bond ends and subsequent alkoxy conversion or by directly
adding trialkoxysilane.
[0039] In another example, a single end hydrolyzable polymer of the following formula:
may be prepared by starting with a fluorooxyalkylene-containing polymer having a carboxyl
group at a single end, effecting Grignard reaction to introduce a plurality of unsaturated
bonds, and adding chlorosilane to unsaturated bond ends and converting into alkoxy
form, or directly adding trialkoxysilane.
[0040] Examples of the dual end hydrolyzable polymer of formula (2) include those wherein
Q, B, and X are combined as shown above for the single end hydrolyzable polymer. Illustrative
examples are given below.
[0041] Preferred examples of the nonfunctional polymer of formula (3) include those of the
general formulae (4) and (5), but are not limited thereto.
Herein p1 and q1 are such numbers that the fluorooxyalkylene-containing polymer may
contain 10 to 100 repeating units.
[0042] Any commercial products may be used as the nonfunctional polymer or component (C).
The polymer is commercially available under the trade name of Fomblin®, for example.
Suitable polymers include the following structures.
[0043] Fomblin Y, typically Fomblin Y25 (Mw: 3,200) and Fomblin Y45 (Mw: 4,100) of the following
structure are available from Solvay Solexis.
Herein p1 and q1 are such numbers as to meet the specified Mw.
[0044] Fomblin Z, typically Fomblin Z03 (Mw: 4,000), Fomblin Z15 (Mw: 8,000), and Fomblin
Z25 (Mw: 9,500) of the following structure are available from Solvay Solexis.
Herein p1 and q1 are such numbers as to meet the specified Mw.
[0045] As used herein, the weight average molecular weight (Mw) is determined by gel permeation
chromatography (GPC) versus polystyrene standards using fluorocarbon Asahiklin AK-225
(Asahi Glass Co., Ltd.) as developing solvent.
[0046] The fluorochemical surface treating agent may comprise a partial (co)hydrolytic condensate
obtained by previously subjecting the terminal hydrolyzable group of the single end
hydrolyzable polymer and/or the dual end hydrolyzable polymer to partial hydrolysis
and condensation in a well-known manner. It is preferred that one partial (co)hydrolytic
condensate contain three or less polymer units, i.e., be trimer or lower, because
a condensate of more than trimer form may be less reactive with the substrate. The
condensate is present in an amount of typically up to 30%, preferably up to 20%, and
more preferably up to 10% by weight, based on the weight of overall solids in the
agent. Within this range, the condensate does not adversely affect solubility in the
solvent and reactivity with the substrate.
[0047] In one embodiment, the fluorochemical surface treating agent comprises (A) a single
end hydrolyzable polymer of formula (1) and/or a partial hydrolytic condensate thereof.
In another embodiment, the surface treating agent may further comprise (B) a dual
end hydrolyzable polymer of formula (2) and/or a partial hydrolytic condensate thereof.
In this embodiment, the content of component (B) is up to 20 mol%, preferably up to
15 mol%, and more preferably up to 10 mol%, based on the total moles of components
(A) and (B). When used, the content of component (B) is preferably at least 0.01 mol%,
more preferably at least 5 mol%. As long as the content of component (B) is in the
range, a film having improved chemical resistance and mar resistance is formed.
[0048] In a further embodiment, the surface treating agent may further comprise (C) a nonfunctional
polymer of formula (3). In this embodiment, the content of component (C) is up to
40 mol%, preferably up to 30 mol%, and more preferably up to 20 mol%, based on the
total moles of components (A), (B) and (C). When used, the content of component (C)
is preferably at least 0.01 mol%, more preferably at least 5 mol%. A content of component
(C) above the upper limit adversely affects chemical resistance.
[0049] To the surface treating agent, other additives may be added, if necessary, as long
as the objects of the invention are not impaired. Suitable hydrolytic condensation
catalysts include organotin compounds such as dibutyltin dimethoxide and dibutyltin
dilaurate, organotitanium compounds such as tetra-n-butyl titanate, organic acids
such as fluorinated carboxylic acids, acetic acid, and methanesulfonic acid, and inorganic
acids such as hydrochloric acid and sulfuric acid. Of these, fluorinated carboxylic
acids, acetic acid, tetra-n-butyl titanate, and dibutyltin dilaurate are preferred.
The catalyst may be added in a catalytic amount, typically 0.01 to 5 parts, more preferably
0.1 to 1 part by weight per 100 parts by weight of components (A) to (C) combined.
[0050] The surface treating agent may be dissolved in a suitable solvent prior to coating.
The solvent in which components (A) to (C) are uniformly dissolved is preferred. Suitable
solvents include fluorine-modified aliphatic hydrocarbon solvents such as pentafluorobutane,
perfluorohexane, perfluoroheptane, perfluorooctane, perfluorocyclohexane, and perfluoro-1,3-dimethylcyclohexane;
fluorine-modified aromatic hydrocarbon solvents such as m-xylene hexafluoride, benzotrifluoride,
and 1,3-trifluoromethylbenzene; fluorine-modified ether solvents such as methyl perfluoropropyl
ether, methyl perfluorobutyl ether, ethyl perfluorobutyl ether, perfluoro(2-butyltetrahydrofuran),
and methoxyperfluoroheptene; fluorine-modified alkylamine solvents such as perfluorotributylamine
and perfluorotripentylamine; hydrocarbon solvents such as petroleum benzine, mineral
spirits, toluene, and xylene; ketone solvents such as acetone, methyl ethyl ketone,
and methyl isobutyl ketone; ether solvents such as tetrahydrofuran and diethyl ether;
ester solvents such as ethyl acetate; and alcohol solvents such as isopropyl alcohol.
Of these, fluorine-modified solvents are desirable for solubility and wettability,
with ethyl perfluorobutyl ether, decafluoropentane, pentafluorobutane, and perfluorohexane
being more desirable. The solvents may be used alone or in admixture.
[0051] An optimum concentration of components (A) to (C) in the solvent is 0.01 to 50% by
weight, especially 0.03 to 20% by weight, though it varies with a particular treating
technique.
[0052] The surface treating agent may be applied to a substrate by any well-known techniques
such as wet coating (e.g., brush coating, dipping, spraying, inkjet coating), evaporation,
and sputtering. Better results are obtained when the agent is applied by spray coating,
evaporation and sputtering. A coating is then cured to the substrate. The curing temperature
varies with a particular curing technique. For example, the curing temperature is
desirably in a range of room temperature (20°C) to 200°C, more desirably 50 to 150°C.
With respect to humidity, humid curing conditions are desirable to accelerate the
reaction. The cured coating has a thickness of typically 0.1 to 100 nm, desirably
3 to 30 nm, and more desirably 5 to 15 nm although the thickness depends on the type
of substrate.
[0053] The substrate to be treated with the surface treating agent is not particularly limited,
and may be made of any desired materials including paper, fabric, metals, metal oxides,
glass, plastics, ceramics, quartz, and sapphire glass. The surface treating agent
is effective for endowing the substrate with water/oil repellency, chemical resistance,
parting properties, and antifouling properties. The substrate may be pretreated on
its surface, for example, by hard coat treatment or antireflective treatment. If the
substrate is less adherent, adhesion may be improved by forming a SiO
2 layer or a layer of a silane coupling agent having hydrolyzable group or SiH group
as the primer layer, or by any well-known pretreatment such as vacuum plasma treatment,
atmospheric plasma treatment, alkali or acid treatment.
[0054] Since the surface treating agent contains hydrolyzable groups, desirably a silicon
oxide (SiO
2) layer is formed on the substrate as a primer before the surface treating agent is
coated thereon. Where the surface treating agent is directly bondable to substrates,
typically glass substrates via hydrolyzable groups, the desired effect may be exerted
without a need for SiO
2 layer.
[0055] Better results are obtained when glass, chemically strengthened glass, physically
strengthened glass, SiO
2-deposited glass, sapphire glass, SiO
2-deposited sapphire glass, quartz substrate, and metal are used as the substrate.
[0056] Various articles may be treated with the fluorochemical surface treating agent. Preferred
articles are optical articles including control panels or displays in car navigation
systems, car audio systems, tablet PCs, smart phones, wearable terminals, mobile phones,
digital cameras, digital video cameras, PDA, portable audio players, game consoles,
LC displays in operation boards and digital signages, organic EL displays, plasma
displays, touch panel displays, eyeglass lenses, camera lenses, lens filters, sunglass,
medical instruments (e.g., gastroscopes), copiers, solar cell panels, protective film,
and antireflective film. Among others, touch panels, antireflective film, wearable
terminals, eyeglass lenses, and solar cell panels are suitable. When an article is
treated with the surface treating agent, the agent forms a film which is effective
for preventing fingerprints or sebum from adhering to the article and for imparting
scratch resistance. The film is most useful as a water/oil repellent layer on touch
panel displays.
[0057] When a substrate such as glass, sapphire glass or SiO
2-deposited substrate (i.e., substrate having SiO
2 deposited by evaporation or sputtering) is treated with the surface treating agent
by spray coating, inkjet coating, spin coating, dipping, vacuum evaporation, or sputtering,
there is obtained an antifoul-treated substrate which has sufficient chemical resistance
and resistance to steel wool abrasion to maintain water/oil repellency over a long
term.
EXAMPLE
[0058] Examples of the invention are given below by way of illustration and not by way of
limitation.
Example 1
[0059] A composition #1 containing components (A) to (C), shown below, was prepared.
p1+q1 = 45, p1/q1 = 1.0,
E = -C
3H
5 : -C
3H
6-Si(OCH
3)
3 = 0.2:1.8,
A:B:C = 92:3:5 (molar ratio)
[0060] The content (molar fraction) of each component (A, B, C) was determined by letting
silica gel adsorb hydrolyzable group-containing polymers for thereby fractionating
component (C), and analyzing by
19F-NMR spectroscopy.
Example 2
[0061] A composition #2 containing components (A) to (C), shown below, was prepared.
p1+q1 = 45, p1/q1 = 1.0,
E = -C
3H
5 : -C
3H
6-Si(OCH
3)
3 = 0.5:1.5,
A:B:C = 90:5:5 (molar ratio)
Example 3
[0062] A composition #3 containing components (A) to (C), shown below, was prepared.
p1+q1 = 30, p1/q1 = 0.9,
E = -C
3H
5 : -C
3H
6-Si(OCH
3)
3 = 0.2:1.8,
A:B:C = 85:5:10 (molar ratio)
Example 4
[0063] A composition #4 containing components (A) to (C), shown below, was prepared.
p1+q1 = 80, p1/q1 = 1.1,
E = -C
3H
5 : -C
3H
6-Si(OCH
3)
3 = 0.2:1.8,
A:B:C = 72:14:14 (molar ratio)
Example 5
[0064] A composition #5 containing components (A) to (C), shown below, was prepared.
(C) CF
3O(CF
2O)
p1(CF
2CF
2O)
q1CF
3
p1+q1 = 45, p1/q1 = 1.0,
A:B:C = 65:12:23 (molar ratio)
Example 6
[0065] A composition #6 containing components (A) to (C), shown below, was prepared.
(C) CF
3O(CF
2O)
p1(CF
2CF
2O)
q1(CF
2CF
2CF
2O)
r1(CF
2CF
2CF
2CF
2O)
s1CF
3
p1+q1 = 45, p1/q1 = 1.1, r1+s1 = 4, r1/s1 = 0.7,
E = -C
3H
5 : -C
3H
6-Si(OCH
3)
3 = 0.2:1.8,
A:B:C = 70:8:22 (molar ratio)
Example 7
[0066] A composition #7 was prepared by mixing 1 mole of composition #1 with 0.5 mole of
nonfunctional perfluoropolyether FOMBLIN Z15 (Solvay Solexis, repeating units: Mw
: 8,000).
Comparative Example 1
[0067] A composition #8 containing components (A) to (C), shown below, was prepared.
(C) CF
3O (CF
2O)
p1(CF
2CF
2O)
q1CF
3
p1+q1 = 45, p1/q1 = 1.0,
E = -C
3H
5 : -C
3H
6-Si(OCH
3)
3 = 1:1,
A:B:C = 88:5:7 (molar ratio)
Comparative Example 2
[0068] A composition #9 containing components (A) to (C), shown below, was prepared.
(C) CF
3O(CF
2O)
p1(CF
2CF
2O)
q1CF
3
p1+q1 = 45, p1/q1 = 0.9,
E = -H : -C
3H
6-Si(OCH
3)
3 = 0.5:2.5,
A:B:C = 90:8:2 (molar ratio)
Comparative Example 3
[0069] A composition #10 was prepared by mixing 1 mole of composition #1 with 0.95 mole
of FOMBLIN Z15.
Comparative Example 4
[0070] A composition #11 containing components (A) to (C), shown below, was prepared.
(C) CF
3O(CF
2O)
p1(CF
2CF
2O)
q1(CF
2CF
2CF
2O)
r1(CF
2CF
2CF
2CF
2O)
s1CF
3
p1+q1 = 45, p1/q1 = 1.1, r1+s1 = 4, r1/s1 = 0.7,
E = -C
3H
5 : -C
3H
6-Si(OCH
3)
3 = 0.2:1.8,
A:B:C = 65:30:5 (molar ratio)
Preparation of surface treating agent and formation of cured film
[0071] Surface treating agents were prepared by dissolving the compositions in solvent Novec®
7200 (ethyl perfluorobutyl ether by 3M) in a concentration of 20 wt% of solids. The
ratios of components in the agent are shown in Table 1.
Table 1
|
Composition |
Component ratio (mol%) |
Rate of functionalization (b) * |
A |
B |
C |
Example |
1 |
1 |
92 |
3 |
5 |
1.8 |
2 |
2 |
90 |
5 |
5 |
1.5 |
3 |
3 |
85 |
5 |
10 |
1.8 |
4 |
4 |
72 |
14 |
14 |
1.8 |
5 |
5 |
65 |
12 |
23 |
2.0 |
6 |
6 |
70 |
8 |
22 |
1.8 |
7 |
7 |
61 |
2 |
37 |
1.8 |
Comparative Example |
1 |
8 |
88 |
5 |
7 |
1.0 |
2 |
9 |
90 |
8 |
2 |
2.5 |
3 |
10 |
47 |
2 |
51 |
1.8 |
4 |
11 |
65 |
30 |
5 |
1.8 |
* Rate of functionalization (b) corresponds to an average of b in formulae (1) and
(2). |
[0072] Onto glass having SiO
2 of 10 nm evaporated on its outermost surface (Gorilla® 2 by Corning, 50 mm × 100
mm), each surface treating agent was deposited by vacuum evaporation under the following
conditions. The deposit was held at 80°C in an atmosphere of humidity 80% for 1 hour,
obtaining a cured film.
Apparatus and conditions of vacuum evaporation
[0073]
Apparatus: |
compact vacuum evaporation unit VPC-250F (ULVAC KIKO Inc.) |
Pressure: |
2.0×10-3 Pa to 3.0×10-2 Pa |
Temperature (ultimate temperature of boat): |
500°C |
Distance: |
20 mm |
Charge of agent: |
10 mg |
Amount evaporated: |
10 mg |
[0074] The cured film was evaluated for water repellency, coefficient of dynamic friction,
chemical resistance and abrasion resistance by the following tests. The tests were
conducted at a temperature of 25°C and a humidity of 50%. The results are shown in
Table 2.
Water repellency
[0075] Using a contact angle meter Drop Master (Kyowa Interface Science Co., Ltd.), the
cured film on glass was measured for a contact angle with water (2 µl droplet) as
an index of water repellency.
Coefficient of dynamic friction
[0076] Using a surface tester 14 FW (Shinto Scientific Co., Ltd.), the cured film was measured
for a coefficient of dynamic friction by rubbing with fabric under the following conditions.
Fabric: |
Bemcot (Asahi Kasei Fibers Corp.) |
Contact area: |
10 mm × 35 mm |
Load: |
100 g |
Chemical resistance
[0077] A chemical resistance test was conducted to determine an index of adhesion. The cured
film was immersed in 1 wt% NaOH aqueous solution for 72 hours before a contact angle
with water was measured as above.
Abrasion resistance
[0078] Using an abrasion tester TriboGear Type 30S (Shinto Scientific Co., Ltd.), the cured
film was rubbed with steel wool. After 10,000 back-and-forth strokes of rubbing, a
contact angle with water was measured as above.
Steel wool: |
#0000 |
Contact area: |
1 cm2 |
Load: |
1 kg |
Table 2
|
Contact angle with water (°) |
coefficient of dynamic friction |
Contact angle with water (°) after chemical test |
Contact angle with water (°) after abrasion test |
Example |
1 |
116 |
0.02 |
110 |
110 |
2 |
115 |
0.02 |
105 |
110 |
3 |
116 |
0.02 |
109 |
111 |
4 |
115 |
0.03 |
111 |
105 |
5 |
115 |
0.03 |
107 |
105 |
6 |
115 |
0.02 |
107 |
108 |
7 |
115 |
0.02 |
105 |
110 |
Comparative Example |
1 |
115 |
0.02 |
97 |
110 |
2 |
115 |
0.03 |
110 |
85 |
3 |
116 |
0.02 |
95 |
110 |
4 |
114 |
0.03 |
111 |
98 |
[0079] It is evident from the test results that Comparative Example 1 exhibits poor adhesion
to the substrate and less chemical resistance due to a low rate of functionalization.
Comparative Example 2 is adherent to the substrate, but exhibits poor resistance to
steel wool abrasion due to a bulky linking group. Comparative Example 3 exhibits poor
adhesion to the substrate and less chemical resistance due to an excessive content
of nonfunctional polymer or component (C). Comparative Example 4 exhibits poor resistance
to steel wool abrasion due to a higher content of dual end hydrolyzable polymer or
component (B).
[0080] In contrast, both chemical resistance and abrasion resistance are met by Examples
in which the content of component (B) is 0.1 to 20 mol% based on the total moles of
components (A) and (B) and the content of component (C) is 0.1 to 40 mol% based on
the total moles of components (A), (B) and (C).
[0081] The fluorochemical surface treating agent cures into a film having improved water/oil
repellency. The agent is quite effective in such applications as touch panel displays
and antireflective film where it is important to keep visibility despite a probability
of oil and fat sticking. Fulfilling both chemical resistance and abrasion resistance,
the film maintains a satisfactory antifouling surface over a long term even when stains
are kept stuck for a long time or under the situation where daily items such as fabrics
and keys frequently come in contact with the film.
[0083] Although some preferred embodiments have been described, many modifications and variations
may be made thereto in light of the above teachings. It is therefore to be understood
that the invention may be practiced otherwise than as specifically described without
departing from the scope of the appended claims.
1. A fluorochemical surface treating agent comprising (A) a hydrolyzable group-containing
silane modified with a fluorooxyalkylene-containing polymer, represented by the average
compositional formula (1) and/or a partial hydrolytic condensate thereof,
wherein A is a monovalent fluorinated group terminated with -CF
3,
Rf is -(CF
2)
d-(OCF
2)
p(OCF
2CF
2)
q(OCF
2CF
2CF
2)
r-(OCF
2CF
2CF
2CF
2)
s(OCF(CF
3)CF
2)
t-O(CF
2)
d-, d is independently an integer of 0 to 5, p, q, r, s and t are each independently
an integer of 0 to 200, p+q+r+s+t is 10 to 200, units in parentheses may be randomly
arranged,
Q is a single bond or a divalent organic group,
B is a divalent group: -J
2C-, a divalent group: -L
2Si-, a trivalent group: -JC=, a trivalent group: -LSi=, a tetravalent group: -C=,
or a tetravalent group: -Si≡, wherein J is independently an alkyl group, hydroxyl
group or silyl ether group: K
3SiO-, K is independently hydrogen, alkyl, aryl or alkoxy, L is independently alkyl,
alkoxy or chloro,
R is a monovalent organic group,
X is a hydrolyzable group, a is an integer of 1 to 3, b is an integer of 1 to 3, an
average of b being 1.5 to 3.0, c is an integer of 1 to 10.
2. The fluorochemical surface treating agent of claim 1, further comprising (B) a hydrolyzable
group-containing silane modified with a fluorooxyalkylene-containing polymer, represented
by the average compositional formula (2) and/or a partial hydrolytic condensate thereof,
component (B) being present in an amount of 0.1 to 20 mol% based on the total moles
of components (A) and (B),
wherein Rf, Q, B, R, X, a, b, and c are as defined in formula (1).
3. The fluorochemical surface treating agent of claim 1 or 2, further comprising (C)
a fluorooxyalkylene-containing polymer having the general formula (3), component (C)
being present in an amount of 0.1 to 40 mol% based on the total moles of components
(A), (B) and (C), provided that component (B) is optional,
D-Rf-D (3)
wherein Rf is as defined in formula (1) and D is independently fluorine, hydrogen,
or a monovalent fluorinated group terminated with -CF3, -CF2H or -CFH2.
4. The fluorochemical surface treating agent of any one of claims 1 to 3, wherein Q is
a single bond or a substituted or unsubstituted, divalent hydrocarbon group of 2 to
12 carbon atoms which may contain at least one structure selected from an amide bond,
ether bond, ester bond, diorganosilylene group, and -Si[OH][(CH2)gSi(CH3)3]- wherein g is an integer of 2 to 4.
5. The fluorochemical surface treating agent of any one of claims 1 to 4, wherein X is
a hydrolyzable group selected from the group consisting of C1-C10 alkoxy groups, C2-C10 alkoxyalkoxy groups, C1-C10 acyloxy groups, C2-C10 alkenyloxy groups, halogen groups, and silazane groups.
6. The fluorochemical surface treating agent of any one of claims 1 to 5, which is diluted
with a solvent.
7. The fluorochemical surface treating agent of claim 6, wherein the solvent is selected
from the group consisting of methyl perfluorobutyl ether, ethyl perfluorobutyl ether,
methoxyperfluoroheptene, decafluoropentane, pentafluorobutane, and perfluorohexane.
8. An article treated with the fluorochemical surface treating agent of any one of claims
1 to 7.
9. An optical article treated with the fluorochemical surface treating agent of any one
of claims 1 to 7.
10. A glass, chemically strengthened glass, physically strengthened glass, SiO2-deposited glass, sapphire glass, SiO2-deposited sapphire glass, quartz substrate, or metal treated with the fluorochemical
surface treating agent of any one of claims 1 to 7.
11. A touch panel, antireflective film, wearable terminal, eyeglass lens, or solar cell
panel treated with the fluorochemical surface treating agent of any one of claims
1 to 7.